Which Spanish explorer, in 1513, was the first European to discover the Pacific Ocean?

In 1513, the Spanish conquistador and governor Vasco Núñez de Balboa was in present-day Panama, where he had established the first permanent European settlement on the American mainland. Driven by rumors from local indigenous peoples of a vast sea and a gold-rich kingdom to the south, he led a grueling expedition. After weeks of hacking through dense jungle and battling hostile (Review) tribes, Balboa climbed a mountain peak on September 25th and became the first European to gaze upon the immense ocean. He named it the Mar del Sur, or "South Sea," because he had traveled south across the isthmus to find it.

Four days later, Balboa reached the shore and waded into the waves, dramatically claiming the sea and all its adjoining lands for the Spanish Crown. This monumental discovery had profound consequences. It confirmed that the Americas were not the eastern edge of Asia but a "New World," a separate continent with another ocean beyond it.

Balboa's discovery of the Mar del Sur directly inspired future expeditions, including Ferdinand (Review) Magellan's quest to circumnavigate the globe, during which he renamed it the Pacific Ocean for its calm waters. More immediately, it opened the western coast of South America to Spanish conquest, paving the way for Francisco Pizarro's subsequent invasion of the Inca Empire that Balboa had heard tales of. His trek across the isthmus was a pivotal moment in the Age of Discovery.